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Fix lock_exclusive()'s behavior during swap step.

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Since we are not starting a new transaction in conn2 during the
swap step, we need to make sure that if our LOCK query is canceled
due to statement_timeout that conn2's transaction is not left in
a useless error state. Use SAVEPOINT and ROLLBACK TO SAVEPOINT to
avoid this problem.
This commit is contained in:
Josh Kupershmidt 2013-06-16 20:17:24 -04:00
parent 9c8d519415
commit 29023206b5
1 changed files with 9 additions and 2 deletions
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11
bin/pg_repack.c
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@ -1404,7 +1404,9 @@ lock_access_share(PGconn *conn, Oid relid, const char *target_name)
* conn: connection to use * conn: connection to use
* relid: OID of relation * relid: OID of relation
* lock_query: LOCK TABLE ... IN ACCESS EXCLUSIVE query to be executed * lock_query: LOCK TABLE ... IN ACCESS EXCLUSIVE query to be executed
* start_xact: whether we need to issue a BEGIN; * start_xact: whether we will issue a BEGIN ourselves. If not, we will
* use a SAVEPOINT and ROLLBACK TO SAVEPOINT if our query
* times out, to avoid leaving the transaction in error state.
*/ */
static bool static bool
lock_exclusive(PGconn *conn, const char *relid, const char *lock_query, bool start_xact) lock_exclusive(PGconn *conn, const char *relid, const char *lock_query, bool start_xact)
@ -1422,6 +1424,8 @@ lock_exclusive(PGconn *conn, const char *relid, const char *lock_query, bool sta
if (start_xact) if (start_xact)
pgut_command(conn, "BEGIN ISOLATION LEVEL READ COMMITTED", 0, NULL); pgut_command(conn, "BEGIN ISOLATION LEVEL READ COMMITTED", 0, NULL);
else
pgut_command(conn, "SAVEPOINT repack_sp1", 0, NULL);
duration = time(NULL) - start; duration = time(NULL) - start;
if (duration > wait_timeout) if (duration > wait_timeout)
@ -1463,7 +1467,10 @@ lock_exclusive(PGconn *conn, const char *relid, const char *lock_query, bool sta
{ {
/* retry if lock conflicted */ /* retry if lock conflicted */
CLEARPGRES(res); CLEARPGRES(res);
pgut_rollback(conn); if (start_xact)
pgut_rollback(conn);
else
pgut_command(conn, "ROLLBACK TO SAVEPOINT repack_sp1", 0, NULL);
continue; continue;
} }
else else